Thread-controlling mechanism



A. H. DE VOE. THREAD CONTROLLING MECHANISM.

' APPLICATION FILED MAY 3!, 1919- 1,416,697,

Patented May 23, 1922.

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. WITNESSES: M=74- ATTORNEY A. H. DE VOE. THREAD CONTROLLING MECHANISM.

' APPLICATION FILED MAY 31, 1919.

Patented May 23, 1922.

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i e 3* e V win: I I. I g Q WITNESSES: mvigigg/ wdfim Mk 0% ATTORNEY ALBERT H. DE 'VOE, OF WESTEIELD, NEVI JERSEY, ASSIGNOR- TO THE SLVGER MANU- FACTURING COMPANY, A CORPORATION OF NET/V JERSEY.

THREAD-CONTROLLING MECHANISM.

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Application filed May 31, 1919.

T 0 all whom-"it may concern:

Be itknownthat I, ilCLBERT H. DE Von, a citizen of the United States, 'residin' at Westfield. in the county of Union and tate of New Jersey, have invented certain new and useful Improvements in Thread-Controlling Mechanism, of which the following is a specification, reference being had thereinto the accompanying drawings.

This invention relates to sewing machines and particularly to mechanism employed therewith for controlling the needle thread during each cycle of stitch-forming operations.

It aims to provide a new and improved mechanism which combines simplicity of construction with a nice capacity for controlling thread.

More specifically it aims to p'rovide a mechanism which will take up thread during the first and last portions of the needles descent in order to'prevent slack forming under the point of the descendin'gneedle and in order to assist the needle in drawing up the previously shed. needle-loop at the lower end 01" itsdownward movement.

It further aims to provide a mechanism which will finally set the stitch during the ascent of the needle as it reaches its upper limit ofmovement and to set the stitch with a gradual pull or strain thereon in a man: her not likely to cause the thread to break.

It "also aims to provide a light and easy 7 running mechanism for controlling the needie thread capable of operation at a high rate of speed.

These are the-objects of my invention and other objects thereof will appear in the following detailed description of the accord panying drawings in which Fig. 1 represents a side elevation of a double thread chain-stitch machine to which the invention has been applied. Fig. 2 represents in full size the take-up tor the needle thread showing the same on the head of the machine which is sectioned vertically and broken away to better expose the mechanism to View. tion through the head of the machine showing the relative arrangement of the parts and Fig. 4 is a detailed view showing in perspective the shape of the thread engaging or contacting portion of the take-up mechanism.

specification of'Letters Patent.

Fig. 8 is a transverse vertical sec-- Patented May 23, 1922.

Serial No. 301,052.

In the illustrated embodiment of the invention the titch-forming instrumentalities proper comprise a pair of diagonally disposed needles 11 and pair of loopers 12. The needles 11 are secured as usual in a needle-clamp 13 having thread guiding fingers 1d for the respective needle threads, the clamp being fixed to the lower end of a needle-bar 15 pivotally connected by the pin 16 to a link 17 which in turn is pinned as indicated at 18 to a vibrator lever 19 fulcrumed on a pin 20 located centrally in the overhanging bracket-arm 21 and driven through the .pitman 22 from a crank 23 on the main-shaft 240i the machine.

The loopers 12 may be of any suitable type and are in the illustrated embodiment of the invention of the thread-carrying type adapted to form a two thread chain-stitch. They may be supported and actuated in any suitable well known way and detailed description thereof is deemed unnecessary.

As more fully. disclosed in my pending application Serial No. 149,719, filed Feb. 20. 1917. theoverhanging arm 21 is grooved longitudinally on its face as indicated by the numeral 25 and nearly covered by a plate 26 which defines with the groove a concealed thread passage for the needlethread extending from the constant supply tension devices 27 to. a point adjacent the dependinghead 28 at the free end of the overhanging a-rm. Inner and outer cover plates 29 and 30 respectively are located at the junction of the head and overhanging arm in spaced relation to permit the passage of the needle thread therebetween and the outer of these plates has :1 depending por tion 31 which is inset in the head 28 and covers a channel 32 therein through which the thread passes freely down to the threadguiding fingers 14 and thence to the needles 11. The plates 29 and 30 are also provided with arcuate openings 33 for a part of the take-up mechanism.

The needle-thread controlling mechanism comprises a stationary thread-guide 34 disposed internally or the concealed thread passage, a movable thread-guide or finger 35 which is secured by a screw 36 to the vibratory needle-lever 19 andwhich projects across the space between plates 29 and 30 through the slots 33, and a take-up Whose active thread contacting portion is of the form and construction indicated clearly in perspective in Fig. iand designated generally by the numeral 37. The take-up plate 37 is adjnstably secured by the screw and slot connection indicated at 38 to a lever 39 which is :fulcrumed to a fixed part of the frame as indicated at 40 and which is actuated by a link ll pinned at 42 to the vibratory needle-lever 19. The plate 37 or takeup proper is provided with a notch 43 at one end and a groove at at its other end and with a lug as intermediate its ends which prevent the needle-thread slipping laterally off the plate. As indicated in Fig. l the cover-plates 29 and are cut away to term the registeringcrescent shaped openings indicated at 46, Fig. 1 only aliording clearance for the take-up proper or plate 37.

In Fig. 2 of the drawings the extremes of movement of a single needle-eye are indicated by the numerals 1 to 5 and intermediate positions by the numerals 2, 3 and 4t. Corresponding positions of the movable thread-guide are indicated by the numerals 1 to 5 respectively and corresponding positions of the opposite ends of the take-up plate 37 are likewise indicated by the numerals 1 to 5 inclusive and 1 to 5" inclusive.

. The respective needles and loopers cooperate to form a two-thread'chainstitch in a manner WCll known the looper entering a loop of thread thrown out by the needle as it begins to ascend and holding the same until the needle in its succeeding descent enters the triangle formed by the looper-thread extending from the eye of the looperto the preceding needle puncture, the needle-loop upon the looper, and the blade of the looper itself, after which the needle-loop upon the looper is shed and drawn up by the further descent of the needle to the lower limit ofits movement.

The desideratum in needle-thread control.- ling mechanism of the chain stitch type" has long been recognized to be a take-up which will draw or endeavor to draw thread back through the eye of the needle during the first and last portions oi": its descent from its highest to its lowest position and which. will at the same time set the stitch. that has just been formed on the innnediately following ascent of the needle to its highest position. The component parts of the thread-controlling mechanism which have been previously descrihei'l indetail are so organized and. arranged in reference to the needle and looper that the desideratum is realized. As the needle descends from its upper limit of movement the thread guide or finger 35 descends at substantially the same rate as the needle-eye, if anything being a little slower.

The needle thread which extends from the fixed'eye over the left hand end of the take-up 37 and across the thread-engaging member 35 and thence passes downwardly to the needles, is not given up to the needle at first as fast as is required and consequently thread is drawn backwardly through the eye of the needle. This results from the retardin action of the left hand endof the take-up plate 37 which, as apparent from an examination of Fig. 2, moves the slight distance between 1 and 2 while the thread engaging member 35 is moved from 1 to 2.

As the needle continues in its descent the same end of the take-up 37 accelerates but its acceleration has no pronounced effect upon the thread until the point of the needle enters or is about to enter. the work. At about the time the needle loop is shed bythe looper the right hand end of the take-up plate 37; which has been moving in a circle upwardly, becomes eitective upon the needlethread between the stationary thread-guide 34. and the movable thread-guide 35 to materially increase the take-up action on the thread. In the subsequent descent of the needle from about the time the needle-loop is shed until the needle reaches its lower limit of movement this right hand end of the take-up 37 continues to pull upon the needle-thread extending from the supply to the needle and'thereby assists the needleeye in drawing the previously shed needleloop up to the work. V i V In the ascent of the needle from its lower to its upper limit of movement the take-up 37 first slackens upon the thread leading to the needle and allows the latter to throw outan abundantly large loop for the entrance ot the looper and after thelooper has entered the needle loop the thread engaging member tends to tighten the needle-loop upon the looper. But the pulling action'of the thread engaging member 35, upon the needle-loop around the looperis gradual be? cause of the modifying giving upraction of the then descending-right hand end of the take-up. As the needle continues to rise the left hand end of the take-up becomes more 7 effective and in cooperation with the thread engaging finger the left hand end of the take-up 37 insures a very gradual setting'of the stitch which is of course not completed until the needle reaches its upper limit of movement. i 7

From observations taken directly from a machine to which the invention has been applied it has been noted that there is a pulling 0a of needle-thread from the supply during the last portion of both the needles descent and ascent.

While the thread controlling mechanism of the present invention "may be" used with the constant tension devices 27 only interposed between it and the source or" supply, it is preferable for certain elassesof work to employ an intermittent thread gripping device or nipperlwhichis indicated on the drawingsby the numeral 47 and it is timed to grip the thread when the needle has almost reached its lower limit of movement in its descent. The nipper releases it grip up on the thread about the time the looper enters the needle-loop and during the ascent of the needle. This nipper may be of any suitable term andmay be operated as more fully disclosed in my prior Patent No. 1,273,157, July 23, 1918.

Having thus set forth the nature of the invention, what I claim herein is- 1. In a sewing machine, in combination, stitch-forming mechanism including a needle, a looper, and thread-controlling mechanism including a stationary thread-guide and a movable threadguidc spaced from the first threadguide, a thread-governing member having spaced threaclengaging portions both of which are located intermediate said guides, and means for moving said member relative to said guides to draw thread back through the eye of the needle during the first part of its descent and before its point reaches the work, and for moving said member relative to said thread-guides to assist the needle in drawing up the previous needleloop after it has been shed by the looper and during the last part of the downward movement of the needle.

2. In a sewing machine having stitchi orming mechanism including a needle and a looper, in combination, thread-controlling mechanism including a stationary threadguide, a second thread-guide movable in unison with the needle, a member having spaced thread-engaging portions intermediate said thread-guides, and means for oscillating said member during each stitch-forming cycle of operations and compelling it in cooperation with said second movable thread-guide to pull upon the needlethread during the first and last portions of the needles descent.

3. A tl11f321(l('011l310lllflg mechanism for sewing machines having a needle comprising a stationary thread-guide, a movable threadguide. a member mounted on a stationarily located pivot and arranged to operate upon the thread extending between said threadguides, and means for moving said pivoted member in a circular path at a variable an gular velocity whereby in cooperation with the movable thread-guide a change in the pulling action upon the thread is effected gradually during the first and last portions ot the ncedles descent.

a, In a sewing machine having stitch- :torming mechanism including a needle and a looper, and in combination therewith, spaced thread-guides and an intermediate threadgoverning member movable about a fixed pivot and having its opposite extremities arranged to alternately exert a dominating action upon the thread extendingbetweensaid thread-guides by bending the thread in e es? the same direction during each stitch-formstroke and first part 01 the up stroke of the needle, and means for moving said member including a link connected at its opposite ends to said member and said vibratory lever, respectively.

6. A thread-controlling mechanism for chain-stitch sewing machines having aneedle and looper comprising relatively movable and spaced thread-guides and an intermediate thread-governing member mounted on a stationarily located pivot and having a flat and relatively long threadengaging portion, and means for moving said member arcuately and its ends oppositely with respect to the direction in which the needle moves, whereby pull is exerted upon the needle-thread during the first and last portions of its descent.

7. In a sewing machine having stitch- ;"orming mechanism including a needle, a bracket arm in which said needle is mounted to reciprocate, and means for reciprocating said needle, in combination, thread-controlling mechanism including spaced threadguides one of which is mounted to move substantially in unison with the needle and a thread-governing member pivoted on the bracket arm between said guides and comprising spaced thread-engaging portions, and a link pivoted to the needle-operating means and said member to oscillate the same about its pivot.

8. In a sewing machine having stitchforming mechanism including a reeiprocating needle, a thread-controlling mechanism including spaced thread-guides, a threadengaging member intermediate said guides having spaced thread-engaging portions, said member being so constructed and arranged that during the first part of the down stroke of the needle one of said portions only engages the thread and moves slowly to cause thread to slide through the eye of the needle and during the latter part of the down stroke of the needle the other portion engages the thread to assist the needle in drawing up the previously shed needle-loop.

9. In a sewing machine having an arm, stitclr'forming mechanism including a reciprocating needle, thread-controlling mechanism including a thread-guicle mounted within the arinnnd adapted to move submechanism including spaced thread-guides located within said arm, a movablethreadengaging member located between said guides and wholly within the arm comprising spaced thread-engaging portions, and means for so 'moving said member that the efiect of one of said portions oncthe thread decreases as the effect of the other increases and vice versa.

In testimony whereof, I have signed my name to this specification.

ALBERT H. DE Von. 

